Method for processing dental acrylic resins

Abstract

A method for using dental acrylic resins, the method comprising mixing a liquid monomer of methyl methacrylate with a polymer powder of methyl methacrylate, forming the mixture into an arbitrary shape by molding, filling, applying or other means, and then polymerizing and curing the formed mixture, wherein organic compounds selected from acryloyl morpholine, a coumarone resin, vinyl stearate, polyvinyl acetate, and alcoholic surfactants are previously added to the liquid monomer as a shrinkage controlling agent for lowering a curing shrinkage caused by the polymerization, is disclosed. According to the invention, not only the curing shrinkage rate of the curing shrinkage generated at the time of polymerization can be readily lowered to 0.3% or less, but also the method of the invention can be applied to a denture, a denture base, a casting pattern, fillers or cements as in the conventional techniques.

What is claimed is: 
     
       1. In a method for using dental acrylic resins which comprises mixing a liquid monomer of methyl methacrylate with a polymer powder of methyl methacrylate, forming the mixture into an arbitrary shape by molding, filling, applying or other means, and then polymerizing and curing the formed mixture, the improvement wherein at least one compound selected from the group consisting of acryloyl morpholine, coumarone resin, vinyl stearate, and alcoholic surfactants and mixtures thereof with polyvinyl acetate is added to the liquid monomer as a shrinkage controlling agent to lower curing shrinkage caused by polymerization. 
     
     
       2. A method for using dental acrylic resins as claimed in claim 1, wherein said shrinkage controlling agent is a mixture of any one of acryloyl morpholine, coumarone resin or polyvinyl acetate with an alcoholic surfactant. 
     
     
       3. A method for using dental acrylic resins as claimed in claim 1, wherein said shrinkage controlling agent is a mixture of either coumarone resin or polyvinyl acetate with acryloyl morpholine and an alcoholic surfactant. 
     
     
       4. A method for using dental acrylic resins as claimed in claim 1, wherein said alcoholic surfactant is isostearyl alcohol. 
     
     
       5. An acrylic resin composition comprising: (a) liquid monomeric methyl methacrylate,   (b) powdered polymeric methyl methacrylate, and   (c) as a shrinkage control agent, at least one compound selected from the group consisting of acryloyl morpholine, coumarone resin, vinyl stearate, an alcoholic surfactant and mixtures of these compounds with polyvinyl acetate.   
     
     
       6. A composition as claimed in claim 5, wherein said shrinkage control agent is a mixture of any one of acryloyl morpholine, coumarone resin or polyvinyl acetate with an alcoholic surfactant. 
     
     
       7. A composition as claimed in claim 5, wherein said shrinkage control agent is a mixture of either coumarone resin or polyvinyl acetate with acryloyl morpholine and an alcoholic surfactant. 
     
     
       8. A composition as claimed in claim 5, wherein said alcoholic surfactant is isostearyl alcohol. 
     
     
       9. A composition according to claim 5, wherein the shrinkage control agent comprises acryloyl morpholine or vinyl stearate and is present in an amount of 5 to 15% based on the weight of monomeric methyl methacrylate. 
     
     
       10. A composition according to claim 5, wherein the shrinkage control agent comprises a polymer of coumarone, and is present in an amount of 0.5 to 10% based on the weight of monomeric methyl methacrylate. 
     
     
       11. A composition according to claim 5, wherein the shrinkage control agent comprises stearyl alcohol, oleyl alcohol, pentadecyl alcohol or pentaerythritol and is present in an amount of 0.1 to 5% based on the weight of monomeric methyl methacrylate.